Each unit while alive is always assigned with one of the available behavioral models. They may be considered as “macros” or “tiny scripts” for unit behavior in certain situations. Behavioral models are purely client-side feature, server isn't aware of them. If client got disconnected, they are no longer applied to any of the units.
At this moment server is fully unaware of unit behavioral models exposed on a client. Server's role is to verify that whatever these models instruct unit to do (e.g., follow another unit) is within the game rules framework.
Since this is a client-only feature, it is not prohibited and generally possible to develop new models and integrate them into a client (including bots).
List of models available in Season 0: